Fragmented QRS and QRS Duration As a Marker of Myocardial Reperfusion Measured by Myocardial Blush Grade in Reperfusion Therapy: Systematic Review and Meta-Analysis.

Myocardial blush grade (MBG) is an indicator of microvascular perfusion and patency and an independent predictor of cardiac outcomes. QRS duration and fragmented QRS (fQRS) before reperfusion and its changes after reperfusion are shown to be associated with MBG. We aimed to assess the latest evidence on the association between fQRS and QRS duration with MBG in reperfusion therapy. We performed a comprehensive search on the association between fQRS and QRS duration in successful/impaired reperfusion measured by MBG. There were a total of 1,311 patients from six studies. A shorter QRS duration immediately and at 60 minutes after reperfusion attempt was associated with successful reperfusion, with a mean difference (MD) of -10.62 ms ([-15.55, -5.70]; p  < 0.001; I 2  = 69%) and -15.66 ms ([-19.96, -11.37]; p  < 0.001; I 2  = 77%), respectively, and upon sensitivity analysis, with exclusion of a study, heterogeneity decreases to 33 and 0%. QRS narrowing immediately and 60 minutes after reperfusion attempt was correlated with reperfusion, with an MD of -10.72 ([-16.57, -4.88] ; p  < 0.001; I 2  = 97%) and -10.93 ([-14.00, -7.85]; p  < 0.001; I 2  = 97%), lesser in impaired reperfusion, respectively. QRS duration on admission was not associated with reperfusion outcome. Two studies reported that fQRS was associated with impaired perfusion, with an odds ratio of 9.88 ([5.62-17.38]; p  < 0.0001) and 4.74 ([2.45-9.20]; p  < 0.0001), respectively. A longer QRS duration immediately and at 60 minutes after reperfusion attempt was associated with impaired perfusion. QRS narrowing after reperfusion attempt was correlated with successful reperfusion. fQRS was also associated with a higher probability of impaired perfusion.